Railroad signaling system



June 26, 1934. HOVEY 1,964,354

RAILROAD S IGNALING SYSTEM Filed Dec. 4, 1930 2 Sheets-Sheet 1 m A E:

Ill/6712B? lil 00631 June 26, 1934.

M. H. HOVEY RAILROAD SIGNALING SYSTEM Filed Dec. 4, 1930 2 Sheets-Sheet 2 I C Ifl l) a TJIIIIIILILZZZF IIZIIlTIISIILIi '---O O "1 l 1 i 1 l J :1 a

Patented June 26, 1934 UNITED STATES PATENT OFFICE RAILROAD SIGNALING SYSTEM Application December 4, 1930, Serial No. 499,886

15 Claims.

This invention relates to railway signaling, and is illustrated as embodied in apparatus suitable for use on single track railroads carrying traflic in both directions. A number of objects are ace complished by this invention. A signaling system which is quicker in operation is provided by the eliminating or reducing of certain delays which were formerly considered necessary to the proper operation of such a system. A system has also been provided in which it is physically impossible, as well as electrically improbable to set up a directional control in both directions at the same time. The new results are accomplished together with the furth r new result of reduced cost of construction since certain units have been omitted as well as certain parts of some relays and other relays have been combined into a single relay.

The system is what is known as an A P B system of the tumble-down variety. A train entering one end of a stretch of track causes a progressive tumble down from clear to danger of all the opposed signals ahead of it to the next siding. As the train progresses through the stretch, a

' similar result behind it is prevented by operation of a directional relay which in the present instance is of the polar-neutral variety, the same polar armature controlling both directions, so that only one can possibly be operated at a time, and this polar armature'is in series with the neutral armature which further prevents operation of a directional control at the wrong time.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation, as will be more fully described and particularly pointed out in the specification, drawings and claims a pended hereto.

In the drawings, which illustrate an embodiment of the device, and wherein like reference characters are used to designate like parts,

Figure 1 is a diagrammatic illustration showing the complete apparatus at one station, and sufficient apparatus on the two sides thereof to illustrate the operation of the complete station;

Figure 2 is a diagrammatic illustration of the central portion of Figure 1 showing the positions of the parts when an eastbound train is on track section 0;

Figure 3 is a diagrammatic view of part of the apparatus shown in Figure 2, especially the directional holding circuits, showing positions of the parts when the train shown in Figure 2 has gone from track section C to track section D; and

Figure 4 is a diagrammatic view illustrating the construction of slow-acting line repeater relay 107, and its connection through polar line relay controllers to the line circuit.

For the sake of simplicity, circuits as a whole have been numbered instead of numbering the individual wires. For this reason it occasionally occurs that on one wire there are several numbers indicating each of the circuits of which that wire is a part. Insofar as possible, the control circuits for signal 1 will be designated with numerals between 100 and 199, control circuits for signal 3 will be designated with numerals from 300 to 399, etc.

Although the invention may take many forms, only one has been chosen for illustration. Along the usual stretch of single trackway, which is divided in the customary insulated track sections A to F including batteries at one end and track relays "7- A to '7F at the other end, are provided signals 1 to 6 which are preferably of the stationary lamp type, Ecarrying lamps (3' (green), Y (yellow) and R ,(red) which of course indicate clear, caution and stop. In the drawings, signals 1, 3 and 5 control the westbound trafiic, while signals 2, a and 6 control the eastbound traffic.

I. Signal lamp circuits The lighting circuits for the lamps of signal 1, each of which includes battery 10 when completed, are circuit 100 for the green lamp, 101 for the yellow lamp and 102 for the red lamp. These lighting circuits are controlled by line relay 103 having the polar armature connectors 104, 105 and 106, and by the line repeater relaylO'l, which operates the neutral armature connectors 108 and 112 in addition to other armatures. -When the armature 112 is dropped, circuit 102 for the red lamp is completed, lighting lamp R through circuit 102. Circuits 100 and 101 are broken at the upper contact for controller 112. When controller 112 is picked up, controller 106 for circuits 100 and ,101 is connected to the battery 10 and if this controller 106 is in its normal posi- II. Line circuits Line relay 103 is normally energized by circuit 115, including battery 30, pole-changing armatures 310 and 311 in their upper positions and track relay armatures 115-D and 1l5-E. When de-energization of relay 307 permits the pole-changing contacts 310 and 311 to drop, relay 103 is either de-energized or energized by reversed polarity through the circuits 115 and 115R. This latter circuit 115-R. may be called the reverse or directional branch of 115 and extends from the positive side of battery 30 to the lower contact for controller 311, through the directional control to be described.

The line repeater relay 107 is also normally energized by line circuit 115 through the extension circuit 116 when the polarity of circuit 115 is normal or through the extension circuit 116-R when the polarity of circuit 116 is reversed. When the polarity of circuit 115 is normal, extension circuit 116 is completed by connectors 104 and 105 on the polar armature of relay 103 and their lefthand contacts and when the polarity of circuit 115 is reversed, the extension circuit 116-Pt is completed by the same controllers 104 and 105 in their reversed or righthand position.

Signal 3 is controlled in the same way through line relay 303 and repeater line relay 307, which are energized through circuit 315, the polarity of which is controlled by controllers 510 and 511 controlled by repeater line relay 507. Signal 2 and signal 4 are also controlled in the same manner, or, in other words, their circuits and parts have been numbered according to the same system but with a different hundreds digit. Thus signal 2 is directly controlled byline relay 203 and repeater line relay 207. These relays are energized by circuit 215, the polarity controllers for which are connectors 410 and 411 adjacent signal 4.

In like manner signal 4 is controlled directly by line relay 403 and repeater line relay 407 which are energized through circuit 415, the polarity of which is controlled by controllers 610 and 611, controlled by repeater line relay 607 which also controls signal 6.

It should be understood that controllers 510 and 511 and 610 and 611 are merely portions of the apparatuses located adjacent to and operating signals 5 and 6 respectively which apparatuses as a whole may be exactly like the apparatus located by signals 3 and 4. In fact, it is preferred that along a stretch of unbroken single trackway, each signal station be like that shown for signals 3 and 4, though at the passing siclings, suitable changes should be made.

III. Line repeater relay The line repeater relay is preferably of the slow pick-up and slow release type disclosed in my prior application Serial No. 480,081, filed September 6, 1930. It includes the usual copper washers 16 for causing a slow release. In this instance, however, the number and arrangement of the washers is such that the release is nearly twice as quick as was formerly considered possible in similar systems of signaling. The armatures of the relay are picked up by the picking up coil 17 which is constantly connected across the two lead wires of circuit 116. There is also provided a retardation coil 18 which is constructed to have a small number of ampere turns and is preferably disconnected when the relay is picked up, but when the relay is de-energized it is connected through armature 108 with the wires of circuit 116, but in such manner that its magnetic field is opposed to the magnetic field of coil 17. It

is also preferable that the coil 18 be closer to the armature than the coil 17, so that its effect may be more immediately felt, probably due to its acting as a shield. The coil 18 is of sufiiciently small ampere turns so that at the end of a given retardation period, the coil 17 will overcome the effect of coil 18 sufiiciently to pick up the armature. This retardation period is of course of sufficient length to prevent the undesirable pickup of relay 103, as when a fast moving single car leaves one track section and permits the track relay to pick up before it causes the effective deenergization of the succeeding track relay. The function of this relay in preventing trouble due to such trains has formerly been accomplished by the use of thermal retardation units which were unsatisfactory either because of greatly increased cost or because of occasional operating difficulties, or both.

The operation of this relay is quite simple. If the relay is de-energized and the circuit 116 is connected to the source of supply through circuit 115, the current simultaneously flows through coils l7 and 18. The coil 18, however, is relatively more effective at first and prevents the pick-up of the armature until the elapse of a given retardation period. At that time, the greater magnetism of coil 1'7 penetrates or overcomes the effect of coil 18 sufficiently to pick up the armature of the relay and open circuit controller 108, which disconnects coil 18. .If the circuit 115 is now broken either permanently or for the purpose of changing its polarity, current ceases to flow through extension circuit 116 or through coil 17. Current is set up in washers 16 by the change of magnetic flux following a break in circuits 115 and 116 and this current acts to retard the drop of magnetic flux, and therefore to retard the release of the armature. The period overwhich the release must be retarded, and which is se- IV. Directional relay Only one directional relay has been illustrated, but it should be recognized that there would normally be one such relay for each signal station, or at least for each signal station intermediate of the passing sidings. The directional relay which has been illustrated has been numbered 9, and includes two opposed coils 119 and 219 which, as indicated by their numbers, control signals 1 and 2 respectively. This relay 9 has two armatures each having thereon a plurality of circuit controllers and each controlled by coils 119 and 219. The neutral armature may be picked up by either coil, but if it were possible that they both be energized simultaneously, their effects would nullify each other and the neutral armature would be released. The neutral armature carries the controllers 91, 92, 93 and 94, the circuits for which will be described later.

The polar armature is swung to the left by coil 119 and to the right by coil 219. This armature carries the controllers 95, 96, 97 and 98 which in the drawings have been illustrated as physically linked together. This showing of a physical connection is merely to emphasize the fact that these controllers must operate together and cannot be divided, some to the left and some to the right. Of course, this unity of action applies to all the controllers mounted on any one armature, even though it is not elsewhere of suflicient importance to illustrate diagrammatically.

The polar branch 115-13. of the line circuit which was described under Title II above, extends from the lower contact of controller 311 to the upper contact of controller 93 and from there through the controllers 93 and 97 to battery 30. Therefore when coil 119 is energized all the controllers in branch circuit 115R are closed, as described.

When coil 219 is energized branch circuit 215- B may be closed through the upper contact of neutral controller 92 and through controller 96 to battery 40. In other words, it may be said that coil 219 operates the directional set up for signal 2, while coil 119 operates said directional set up for signal 1.

V. Directional relay circuits The relay coil 219 is initially energized through circuit 220 which, as shown in heavy lines in Figure 2, may be traced from the positive side of the battery through the lower contact of controller 92 through the coil 219 through the upper contact of controller 409 on the armature of repeater line relay 407 and through the back contact of controller 313 on the armature of repeater line relay 307 back to battery 40. As soon as this circuit has been closed, the polar armature of directional relay 9 flops to the right to the position shown in Figure 2 so that the polar branch 220-P of the same directional relay circuit 220 is closed. The circuit 220 then remains the same except that instead of passing through controller 92, which it cannot do when that picks up, it passes through controller 96.

Once this circuit 220 has been eifective to energize the coil 219 to cause a pick-up of relay 9 either one of the directional relay holding or stick branch circuits shown best in Figure 3 may be effective.

The holding circuits extend from the positive side of the battery 40 over pick-up circuit 220 (and its branch 220-1) through the directional set-up coil 219 and then return to the battery through circuit 220 to junction point 223 or to controller 409, and then either through branch holding circuit 221 or branch holding circuit 222. The branch holding circuit 221 branches off from pick-up circuit 220 at point 223 and then it goes through the back contact of controller 221- -D operated by track relay 7-D and continues in branch circuit 221 through controller 94 of the directional relay 9 and through polar controller 98 back to the negative side of battery 40. The branch holding circuit 222 leaves the circuit 220 through the back contact of controller 409 and J'oins branch circuit 221 at the point 224 returning through it via armatures 94 and 98 to the battery 40.

The pick-up and holding circuits for directional set-up coil 119 are just the same except that they are numbered 120, 121, and 122 respectively, and they pass from battery 30 through either neutral armature 93' or polar armature 97 through the coil 119 to the point 123, where they split as follows: Pick-up circuit 120 passes from the point 123 through controller 309 at its front contact through the back contact of controller 413 back to battery 30. The first holding circuit 121 passes from the point 123 through the back contact of controller 121C operated by track relay 7C through the front contact of controller 91 and through controller back to battery 30. The second holding branch circuit 122 extends from controller 309 through its back contact to join circuit 121 at the point 124, from which it returns to the battery thru armatures 91 and 95.

VI. Operation of the tumble-down feature Figure 1 illustrates the parts in their normal positions when the track is entirely clear. If an eastbound train should enter track section B from track section A it would set the opposed, i. e. westbound, signals 1 and 3 to danger through the operation of what is known as the tumble-down system. It should be understood that normally this system would have operated before the train had reached section B, but for the sake of simplicity this fact will be ignored, and the operation will be traced as though the train were entering track section B from an insulated siding.

The train entering section B shunts the track circuit, causing a de-energization of track relay 7-B. This permits controllers 215B and 315B to drop open. The controller 315B starts the operation of the tumble-down feature; controller 215--B merely setting up a danger indication at signal 2 to protect the rear of the train.

Controller 315B breaks circuit 315 which simultaneously de-energizes line relay 303 and repeater line relay 307. It should be noted that this simultaneous de-energizing is very advantageous, for in former light signal systems the setting to danger of the opposed signal 3 was delayed, first, while relay 303 became de-energized and then while relay 307 became de-energized. Now, delay due to the de-energization of relay 303 is entirely obviated and even the delay of relay 307 has been nearly cut in half. Obviously this saving of time will sometimes be enough to prevent an opposed train entering the far end of the block while the apparatus is in the process of changing to the danger indication.

The de-energization of relay 307 has both a primary and a secondary effect, the two eifects, however, being simultaneous. Its primary effect is to change the clear indication of signal 3 to danger indication. This it does by dropping controller 312 from its front contact to its back contact, thus breaking green lamp signal circuit 300 and completing circuit 302 to the red lamp of signal 3.

The secondary result of the de-energization of relay 307 is to send ahead a tumble-down efiect. This it does by dropping armatures 310 and 311 to open line circuit 115 of line relay 103. As the directional relay 9 has not been operated to close the reverse polarity branch 115 R of the line circuit 115, the line circuit 115 becomes completely dead. This results in the simultaneous de-energization of line relay 103 with line relay 107. The de-energization of repeater line relay'107 accomplishes the primary result of changing the indicating of signal 1 from clear to danger. This it does by dropping armature 109 as formerly described. If further sections of the track were shown, the tumble-down effect would be sent ahead by relay 107 and subsequent corresponding relays to the first passing siding to the east.

VII. Polar operation of the permissive indication As the hypothetical train travels from section B to section C it continues its prior effect, inas much as the relay 7-C opens circuits 215 and 315 as did track relay 7--B. When the train passes to section D it de-energizes track relay 7-D, which breaks line circuit 415 by releasing controller 415-D. This causes a de-energization of line relay 403 and repeater line relay 407 and the deenergization of repeater line relay 407 has a primary result of changing the indication of signal 4 from clear to danger. This it does by releasing controller 412 to open circuit 400, through the front contact and to close circuit 402 through the back contact.

If there were no special means to prevent it, the de-energization of relay 407 would have the secondary result of carrying the tumble-down effect back to signal 2 by breaking line circuit 215. The means for preventing this are found in the relay 9 with its directional set up features. This feature will be described below, under Title VIII, but for present purposes we will consider that the armatures have been operated to the position shown in Figure 2, with controller 92 on its front contact and controller 96 closed on its only contact. These two controllers being thus closed complete the reverse polarity branch 215-R of circuit 215. When line repeater relay 407 is now de-energized the dropping of armatures 410 and 411 disconnect line circuit 215 from the battery in normal polarity, and reconnect it in reverse polarity, using branch 215-R. It follows that as soon as the train is clear of track section C so that controller 215-C is closed, current of reverse polarity is sent back through line circuit 215 to line relay 203, and line repeater relay 207. As these relays had formerly been de-energized, armature 212 was in its released position completing circuit 202 to light the red danger indication lamp of signal 2. When the current of reverse polarity reaches relay 203, it almost instantaneously flops the armature of relay 203 to the right, moving controllers 204, 205 and 206 to complete connections with the righthand contacts and to connect the repeater line relay 207 to line circuit 215 through reversed. connection 4 branch 2l6-R. As soon as the current in line circuit 215 has energized relay 207 sufiiciently for its coil 17 (see Figure 4) to have overcome its coil 18 as described above under Title III, relay 207 will pick up its armature. This operation shifts controller 212 to open circuit 202 terminating the red indication and to complete circuit 201 through the upper contact of controller 212 and through the right contact of controller 206, to set up the caution indication by lighting the yellow light.

If we now suppose that the train passes eastward beyond signal 1, that is, clear of track section E, the directional set up at that point would be operated in like manner to energize relays 403 and 407 through circuit 415, which would be connected to battery 60 with reversed polarity through branch 415-R. The directional set up apparatus has not been shown for the position of signal 1, but it is to be understood that it would be the same as that adjacent signals 3 and 4 unless varied because of the presence of a siding. The energization of relay 407 together with the reverse energization of relay 403 would have the primary result or" changing the indication of signal 4 from danger to caution, as described with respect to signal 2. It would have the secondary though almost simultaneous effect of causing signal 2 to change from a caution indication to a clear indication. This it does by bringing circuit controllers 410 and 411 forward to their normal condition. This change disconnects line circuit 215 from its reversed polarity branch 215-R and connects it in its normal polarity to battery 40. This reversal (return to normal polarity) of current in line 215 substantially instantaneously flops the polar armature of relay 203 to its normal or left position.

During the change of polarity of line circuit 215, and the time of flopping of said polar armature, relay 207 is maintained energized by the washers 16 (see Figure 4). The flopping over of said polar armature flops controllers 204 and 205, so that the current in normal direction reaches relay 207 energizing it with the same polarity with which it was energized previously. In other words, a reversal of current in line circuit 215 is almost instantaneously accompanied by a reversal of the connections between the repeater line relay 207 and line circuit 215, so that there is substantially no reversal of current in repeater line relay 207. When the polar armature of relay 203 flops as above described to its normal position at the left, it not only fiops controller 204 and 205, but also flops controller 206, thus breaking circuit 201 to the yellow light and completing circuit 200 to the green light, so that the following train which is two blocks removed from the preceding train may follow at full speed.

VIII. Directional operation The directional set up begins to operate as soon as the train comes into section B, or simultaneously with the operation of the tumble-down feature. When, due to the operation of the tumble-down feature, or due to the release of armature 315B of track relay 7B the line relays 303 and 307 become deenergized, the controller 313, operated by relay 307, is released to complete the pick-up circuit 220 for directional set-up coil 219. This first flops the polar armature 96 to the right unless it was already in that position, thus completing the 220-P branch of the pick-up circuit and either simultaneously therewith or slightly thereafter, the neutral armature is raised, picking up the controller 92 and opening its lower contact so that the original pick-up circuit 220 is broken. At the same time controller 93 is raised, opening its lower contact so that the pick-up circuit 120 for directional setup coil 119 is opened and inasmuch as the other branch 120P of the same pick-up circuit is also opened due to the controller 97 having been swung to the right, it is now impossible for coil 119 to become energized. An adjacent track relay controller may be inserted in each pick-up circuit either as an added safeguard or in place of the controllers 313 and 413.

The various parts remain in the same position described until the train reaches track section C, at which time the only change of interest is to drop the controller 121-C on its back contact closing that break in the first holding circuit 121 for the directional set-up coil 119. Closing controller 121-C is ineffective, however, as the circuit remains open at controller 95 which, as before stated, has swung to the right. The circuit 121 is also broken in its 120 portion at the controllers 93 and 97 as above described.

Whenthe train travels into section B the directional set-up first becomes efiective. As stated 1 under Title VII, the tumble-down feature would be sent back at this time if it were not for the directional set-up. The train entering section D causes de-energization of relays 403 and 407. The de-energization of relay 407 causes a dropping of armature 409 which breaks the pick-up circuit 220 together with its branch 220-P. However, while the relay 407 is in process of de-energizing and before it releases the controller 409, the controller 221-D, released simultaneously with the release of controller 415-D, drops onto its back contact to complete the holding circuit 221 for the directional set-up coil 219. The other breaks in holding circuit 221 have formerly been closed by armature 94 when it was picked up and by armature 98 when it was shifted to the right.

While the directional relay 9 is energized this position as shown in Figure 3, the controllers 92 and 96 close the breaks in the directional branch circuit 215--R so that as soon as track relay 7C picks up due to the train passing from track section C, the circuit 215 through its branch 215-R will be completed with reversed polarity, so that signal 2 will change from the danger to the caution indication.

It is of course necessary for this directional set-up to continue as long as the line repeater relay 407 is de-energized, for during that time the controllers 410 and 411 are in their lower positions, so that line circuit 215 would be dead unless the directional set-up continued. In other words, it is necessary for the directional set-up to continue as long as relay 407 is de-energized, in order to prevent signal 2 from shifting back to a danger indication. The continuation of the directional set-up is accomplished by means of the second holding circuit 222 which is completed by the release of armature 409 to its back contact. With the second holding circuit 222 thus completed, the opening of controller 221-D and the consequent breaking of holding circuit 221 when the train leaves track section D has no effect.

When the train continues into track section F and clear of track section E, line repeater relay 407 picks up as formerly described under Title VII, breaks the holding circuit 222 and simultaneously completes the entire line circuit 215 to energize line relay 203 in a normal direction and change signal 2 to the clear indication. When the holding circuit 222 is thus broken by the raising of controller 409 the directional relay 9 becomes completely de-energized, all of the controllers being in their normal positions, as shown in Figure 1.

Although the operation of the system has been described for the movement of a train in one direction only, it operates in the same manner, only reversed, for the movement of a train in the opposite direction.

IX. Double tumble-down operation It should be noted that with the circuit illustrated, the directional features will not be effective when an isolated track section is shunted, as by the opening of a track switch or by a stationary electrically conductive obstruction on the rails. For example, let up suppose that section C is provided with a switch of a common type, the operation of which shunts across the rails of the section. If such a switch were operated, the first effect would be a de-energization of track relay 7C, which would release controllers 315C and 215-C. The controller 215-C would start the operation of the tumble-down system for signal 2 and any signals therebeyond controlling traffic approaching section C. The controller 315C would likewise start the tumble-down operation as to signals 3, 1, etc. Explaining more fully the controller 315-C would cause the de-energization of line relays 303 and 307 which through the controllers 310 and 311 would interrupt line circuit 115 and cause the de-energization of line relays 103 and 107. This seems very simple, but it must be remembered that if the directional set-up ren lay 9 should operate at this time the line circuit 115 would not be broken and the signal 1 would indicate caution instead of danger, and the signals therebeyond controlling the approach to section C would indicate clear. In former systems of this type the directional set-up would have operated with the potential disastrous result that if the switch in section C was thrown for the purpose of permitting the train to enter section C, such a train would be obstructing the track and might be moving eastward at the same time that a train passed the signal 1 moving westward, relying on the caution indication of signal 1 as meaning that the train ahead was moving away instead of approaching. To overcome this potential danger it has been found necessary in former systems to provide special electrical controllers operated by the switches which would break the line circuits, and often it was necessary to provide long connecting wires between such controllers and a distant line circuit which it was necessary to break. I

In the present circuit, the effective operation of the directional relay 9 is prevented since this operation as to signal 1 requires a completion of circuit 120, which circuit can only be completed when the back contact of controller 413 is closed. Controller 413 is controlled by line relay 407, which is controlled by track sections D, E, F, etc.

Therefore, the directional relay 9 can only be lie 215 is inescapably broken at controller 215-C,

such operation of directional relay 9 is inefiective. Of course, it would be effective if the train entering section C continues on, clear of section C into section D; but if the train has done this, it would be proper for the directional set-up to become effective, for the train would then have established its direction of motion, and it would be desirable for additional trains to be able to follow in the same direction.

It should be noted that there are a number of novel features which go to make up this invention, and that any one of them could be used without the others, either entirely alone, or in combination with other systems. The complete assemblage of these novel features provides a basic signaling system which accomplishes all the results of the former basic systems, permits the same train movements formerly permitted and at the same time is more satisfactory in that the time for operation of the signals is much more rapid than formerly. Obviously some features which can be added to other basic systems may also be added to this one.

The system is more reliable for several reasons. Trouble giving units, such as a thermal retardation unit for the line repeater relays have been done away with and replaced by more reliable substitutes. Some of the dangers of sticking contacts have been avoided. Most notably among these are the contacts for controlling the repeater line relay and for the directional or reversed polarity branches of the line circuits. Although there are still control contacts for the repeater line relay, there is no danger due to their sticking, as the current to the line repeater relay is the line current, so that when the line circuit is broken, relay 207 becomes de-energized whether the repeater contacts stick or not. Even if one of the directional contacts stuck there would be no danger, since the contact in series therewith probably would not stick at the same time, and since the sticking of a contact for one direction makes it both physically and electrically impossible to operate the directional set up for the other direction.

The system is cheaper to build, since the neutral armature has been eliminated from the line relays 203, etc., and since the two directional relays formerly needed, have been replaced by a single directional relay. These changes not only reduce the cost of the operating parts, but they also permit the use of a smaller sized instrument box, with a resultant saving at that point.

It is to be understood that I do not wish to be limited by the exact embodiments of the device shown, which are merely by way of illustration and not limitation, as various and other forms of the device will of course be apparent to those skilled in the art without departure from the spirit of the invention or the scope of the claims.

I claim:

1. A stretch of track, two opposed sets of sig nals thereon, each set including a forward signal and a rear signal, means for each of said forward signals to cause it to indicate danger when a portion of the track in advance of said signal is occupied, tumble-down means for each of said rear signals associated with the forward signals to normally cause it to indicate danger when the corresponding forward signal indicates danger, and a single directionally controlled member carrying contacts for causing alternatively either of said tumble-down means to be rendered ineffective in accordance with the direction of movement of the train, said member being physically incapable of rendering both ineffective simultaneously.

2. A stretch of track, two opposed sets of signals thereon, each set including a forward signal and a rear signal, means for each of said forward signals to cause it to indicate danger when a portion of the track in advance of said signal is occupied, tumble-down means associated with the forward signals for each of said rear signals to normally cause it to indicate danger when the corresponding forward signal indicates danger, and directional means for causing alternatively either of said tumble-down means to be rendered ineffective in accordance with the direction of movement of the train, said directional means being actuated by alternatively either of two opposed coils.

3. A stretch of track, two opposed sets of signals thereon, each set including a forward signal and a rear signal, means for each of said forward signals to cause it to indicate danger when a portion of the track in advance of said signal is occupied, tumble-down means associated with the forward signals for each of said rear signals to normally cause it to indicate danger when the corresponding forward signal indicates danger, and a polar armature for causing alternatively either of said tumble-down means to be rendered ineffective in accordance with the direction of movement of the train, said polar armature being actuated by alternatively either of two opposed coils.

4. A single track railroad signaling system including track circuits and track relays, opposed sets of forward and rear signals; operating means for each set including a line circuit controlled by certain track relays, two line relays in parallel operated by said line circuit, one of said line relays reversing the connections between said line circuit and said other line relay, which latter operates a polarity changer, a rear line circuit for governing said rear signal and having two branches, one passing through each side of said polarity changer, a directional circuit controller included in one of said branches for each set and a coil for operating said controller, and directional means for energizing said coil when a train travels in the direction governed by said rear line circuit only; both of said directional circuit controllers being rigidly connected, and only one being closable at a time.

5. A single track railroad signaling system including track circuits and track relays, opposed sets of forward and rear signals; operating means for each set including a line circuit controlled by certain track relays, two line relays in parallel operated by said line circuit, one of said line relays reversing the connections between said line circuit and said other line relay, which latter operates a polarity changer, a rear line circuit for governing said rear signal and having two branches, one passing through each side of said polarity changer, a directional circuit controller included in one of said branches for each set and a coil for operating said controller, and directional means for energizing said coil when a train travels in the direction governed by said rear line circuit only; both of said directional circuit controllers being rigidly connected, and only one being closable at a time, and means for preventing either of said directional circuit controllers from being effectively closed if both of said coils are energized.

6. A single track railroad signaling system including track circuits and track relays, opposed sets of forward and rear signals; operating means for each set including a line circuit controlled by certain track relays, two line relays in parallel operated by said line circuit, one of said line relays reversing the connections between said line circuit and said other line relay, which latter operates a polarity changer, a rear line circuit for governing said rear signal and having two branches, one passing through each side of said polarity changer, a directional circuit controller included in one of said branches for each set, a coil for operating said controller, directional means for energizing said coil when a train travels in the direction governed by said rear line circuit only; both of said directional circuit controllers being rigidly connected, and only one being closable at a time, means for preventing either of said directional circuit controllers from being effectively closed when both of said coils are energized, and a neutral armature operated by said one or more of the line relays, and a line relay operated by said line circuit, a two-position switch operated by said line relay, a rear line circuit for governing said rear signal, said circuit including two relays one of which reverses the connections between said circuit and the other in response to a reversal of current in said circuit, said rear line circuit having two branches, one closed by said two-position switch in each of its positions, a directional circuit controller included in one of said branches for each set, a coil for each set for operating said controller, directional means for energizing each said coil only when a train travels in the direction governed by said rear line circuit; both of said directional circuit controllers being rigidly connected and only one being closable at a time.

8. A signal system including a plurality of sets of apparatus, each set including a westbound line relay, an eastbound line relay, a westbound line circuit controlled by said westbound line relay, and an eastbound line circuit controlled by said eastbound line relay; a directional relay coil, an armature controlled thereby for controlling said eastbound line circuit, and a local circuit the closing of which is necessary for the initial energization of said coil, said local circuit including two controllers, one closed by the energization of said eastbound line relay and the other closed by the release of said westbound line relay.

9. A signal system including a plurality of sets of apparatus, each set including a westbound line relay, an eastbound line relay, a westbound line circuit controlled by said westbound line relay, and an eastbound line circuit controlled by said eastbound line relay; a directional relay coil, an armature controlled thereby for controlling said eastbound line circuit, a local circuit the closing of which is necessary for the initial energization of said coil, said local circuit including two controllers, one closed by the energization of said eastbound line relay and the other closed by the release of said westbound line relay, and a holding circuit for said directional relay coil closed by the de-energization of said eastbound line relay.

10. A signal system including a plurality of spaced track devices operable by the presence of a train on the adjacent track, a plurality of line circuits each subject to being broken by one of said track devices and controlling a signal behind said device, directional signal control means for each line circuit ahead of its track device, a local sole initial operating circuit for each directional means, means for closing each said initial operating circuit closable only by operation of track devices behind said directional means, said directional means being inelfective to aifect signals behind such track devices while such track devices are operated.

11. A signaling system incuding opposed signals separated by a plurality of track circuit sections, an intermediate control unit, a signaling circuit for each of said signals extending to said intermediate control unit, said intermediate control unit including a separate directional relay coil for each signaling circuit, means to energize each of said coils with one polarity only, and separate contacts in each signaling circuit closeable by the coil for said signaling circuit only, the contacts in the two signaling circuits being physically connected and so arranged that they cannot be closed simultaneously.

12. A signaling system including opposed signals separated by a plurality of track circuit sections, an intermediate control unit, a signaling circuit for each of said signals extending to said intermediate control unit, said intermediate control unit including a separate directional relay coil for each signaling circuit, means to energize each of said coils with one polarity only, and separate contacts in each signaling circuit closeable by the coil for said signaling circuit only, and a pair of contacts in series with said first named contacts and closeable by a neutral armature operable by either of said coils alone but not by both, the polarity of the coils being opposed.

13. A signaling system including opposed signals separated by a plurality of track circuit sections, an intermediate control unit of apparatus, a signaling circuit for each of said signals extending to said intermediate control unit; said intermediate control unit including tumble-down means for each of said signaling circuits tending to interrupt the same when the track on the opposite side of said intermediate control unit is occu pied; a separate directional relay coil for each signal, means to energize each of said coils with one polarity only, and separate contacts for nullifying each of said tumble-down means closeable by the respective coil only, these separate contacts being physically connected and so arranged that they cannot be operated simultaneously.

14. A signaling system including opposed signals separated by a plurality of track circuit sections, an intermediate control unit, a signaling circuit for each of said signals extending to said intermediate control unit, said intermediate control unit including tumble-down means for each 110 of said signaling circuits tending to interrupt the same when the track on the opposite side of said intermediate control unit is occupied, and directional means to nullify said tumble-down means including a pair of coils, connections for each 115 coil for energizing said coil with one polarity of current only, said connections being such that the magnetism of the two coils oppose each other, a polar armature operated in one direction by one of said coils and in the other direction by the other of said coils, and contacts closed by said polar armature in each direction for nullifying said tumble-down means for each signal respectively.

15. A signaling system including opposed signals separated by a plurality of track circuit sections, an intermediate control unit, a signaling circuit for each of said signals extending to said intermediate control unit, said intermediate control unit including tumble-down means for each 130 of said signaling circuits tending to interrupt the same when the track on the opposite side of said intermediate control unit is occupied; and directional means to nullify said tumble-down means including a pair of coils, connections for each coil for energizing said coil with one polarity of current only, said connections being such that the magnetism of the two coils oppose each other, a polar armature operated in one direction by one of said coils and in the other direction by the other of said coils, contacts closed by said polar armature in each direction for nullifying said tumble-down means for each signal respectively, each pair of contacts being connected in series with contacts on a neutral armature operable by 3145 either one of said coils but not by both at once.

MARK H. HOVEY. 

